Torque wrench



April 14, 1942. K. R. LARSON TORQUE WRENCH Filed Oct. 1, 1938 as 2928 I4 1 9 2 Sheets-Sheet 2 M w w W KENNETH R. LARSON.

ll l3 l 12 12W 22 27 By HAAA] .FI 6.1 O. ATTORNEY.

2 features of thepresent invention.

Patented Apr. 14, 1942 2.219.792 TORQUE WRENCH Kenneth R. Larson, Des Plaines, Ill., assignor, by direct and mesne assignments, to Automotive Maintenance Machi 111., a corporation nery 00., of Illinois North Chicago,

Application October 1, 1938, Serial No. 232,723

32 Claims.

This invention relates to more particularly to nut turning wrenches, although certain features thereof may be employed with equal advantage for other purposes.

It contemplates more especially the provision of a simple, dependable, accurate and compact torque wrench that will instantly measure the force supplied in nut turning and similar movements.

Numerous types of torque turning wrenches have heretofore been proposed, but these have not proven entirely satisfactory owing to their substantially increased bulk over ordinary nut turning tools and their failure to render a dependable and uniform service in gauging the torque applied in any nut or other fastening expedient such as a screw. There has been a long felt want for a torque turning tool that is simple, compact, dependable, accurate, and instantly'indicates the desired tension or torque applied to a nut or other fastening expedient.

One object of the present invention is'to simplify the construction and improve the operation of devices of the character mentioned.

Another object is to provide a simple and compact torque indicating wrench that is dependable in operation.

Still another object is to provide an improved turning tool having dependable torque indicating means associated therewith for measuring the torque applied in the turning operation.

A further object is to provide a turning tool with a. single beam for flexing responsive to the application of ents such as nuts, screws, and the like to measure the torque with which such is being applied.

A still further object is to provide an improved nut turning wrench having a single beam in the form of a uniform rod that is operatively connected to a torque indicator at its point of greatest flexing displacement.

Still a further object is to provide a wrench having a single elongated rod disposed longitudinally therein for flexing responsive to the application of force in nut turning to indicate the torque of'applied force commensurate with the instant of flexing at one extremity thereof.

Other objects and advantages will appear from the following description of an illustrative embodiment of the present invention.

In the drawings:

force in turning fastening expedi-.

turning devices and Y shank or body ll cast or handle ill with its chambered Figure 3 is a bottom plan view of the wrench shown in Figure 1, part of the handle being broken away for convenience.

Figure 4 is a sectional view taken substantially along line IV-IV of Figure 3.

Figure 5 is a sectional view taken substantially along line V-V of Figure 3, and Figure 9.

Figure 6 is a sectional view taken substantially along line VI-VI of Figures 3 and 9.

Figure 7 is a sectional view taken substantially along line VII-VII of Figure 8.

Figure 8 is a bottom view of the wrench shown in Figure 3 with the bottom plate removed to il lustrate the inner construction, the handle being broken away for convenience.

Figure 9 is a sectional view taken substantially along line IXIX of Figure 1.

Figure 10 is a fragmentary broken view taken substantially along line X-X of Figure 9.

Figure 11 is a plan view of an indicator mechanism viewed substantially from line X[X[ of Figure 9 with the dial removed therefrom.

Figure 12 is a sectional view of the indicator mechanism taken substantially along line XII-XII of Figures 9 and 13.

Figure 13 is an enlarged sectional view of the indicator mechanism taken substantially along line IHII-XIII of Figures 1 and 8.

The structure selected for illustration comprises a solid handle member III of standard construction having an elongated chambered wrench otherwise shaped to present inclined side walls [2 and I3 to terminate in a semi-circular extremity or head It. The

body I l is preferably though not essentially cast from an aluminum alloy so as to possess the desired strength and lightness for convenience and manipulation in nut turning as will appear more fully hereinafter. It will be observed that the handle shank or body ll consists of the inclined side-walls l2-l3 which converge in the direction of the handle l0 'withan intermediate body wall 15 Figure 1 is a plan view of a wrench embodying Figure 2 is a side-view in elevation of wrench shown in Figure 1.

the V formed integral therewith to figuration of the body wall l8 that extends around the side walls define an elongated chambered interior l6.

Theshank H is normally covered by a solid plate l'l that is shaped to conform with the conl5 to confront therewith and serve as a complement of an open Iedge I 2 3 of the semi-circular extremity I, the face plate I! being shaped to correspond therewith and its lower "nclined edge I 9 cooperates with a correspondingly inclined recess 20 (Figures 2 and 9) formed in the shank ll proximate to the solid 2 handle III. A plurality of threaded screw fasteners 2| project through apertures in the plate I! to engage correspondingly threaded bores 22 in the edge l9 that extends along the side walls l2-l2 of the handle shank or body II and end ll, thereby enclosing the chamber l9 and confining the torque resisting instrumentalities and measuring instriunentalities to be described hereinafter.

It will be noted that the handle shank or body I! and especially the inclined side walls l2-l9 are reinforced in the region of the threaded bores 22 by increasing the thickness of the cast metal as at 22-2, 25-29 and 21 which is a solid portion of the handle shank ll proximate .to the lower extremity of the chamber l9 provided therein. The semi-circular head ll of the body II is provided with a circular recess 29 corresponding in curvature therewith and measured to receive an accurately fitting revolubleor turning head member 29 of corresponding shape and rods 99 and the mount 32. The reduced rod 49 has a pin 43 which projects transversely therethroughsize for rotary association therein. It is to be noted that the circular recess '29 communicates with the chamber IS in the handle shank H, and the entire head portion isreinforced by the enlarged thicknesses 23-24 of the side walls l2-l2 in the region of the recess 29.

Now, then, the enlarged thicknesses 25-29 of the side walls l2-l9 are approximately along a transverse median line of the handle l9 and its contiguous shank or body II, and these are circularly recessed to provideinterrupted arcuate portions 90 and II which receive a cylindrical hearing or bushing 32 of pressed or other suitable material. The bushing 92 is provided with a diametrically disposed bore 39 which freely receives a closely fitting cylindrical rod 99 that extends therethrough from the revoluble member 29 to serve as a torque resisting beam.

To this end, the cylindrical elongated rod 24 is, in this instance, of uniform diameter and projects diametrically through the revoluble member 29 as at 35 for fixed engagement therewith to constitute a single acting unit or memher. As shown, the revoluble member 29 has a transversely disposed cylindrical extension 29 which is joumalled in acorrespondingly shaped aperture 31 provided in the cover plate 11. The cylindrical extension 39 is, in this instance, formed integral with the revoluble member 29 and terminates beyond the cover plate I! in a polygonal shank 28 for registry with a correspondingly shaped and sized recess formed in the wrench socket or other turning implement as commercial practice may dictate for use therewith.

It will be observed, therefore, that any wrench socket of standard construction may be detachably associated with the journalled shank 99 that is preferably though not essentially provided with a spring impelled ball detent 29 to preclude accidental separation therewith. While the elongated beam terminatesjust beyond the bear ing or bushing 32, in this instance, which serves as a floating mount therefor, it should be appreciated that such may extend appreciably therebeyond depending upon the dictates of commercial practice. It has been found more proficient, however, from a manufacturing standpoint to terminate the elongated cylindricalbeam 94 just beyond the floating mount 92 thereof and join therewith a smaller elongated rod 49 of comparatively smaller diameter for pressed fitting axial engagement in an end bore ll provided in the free extremity of the elongated beam 99. This effects the equivalent of an integral ioinder between the beam 94 and its reduced extension 99 that terminates proximately to the lower end 92 of the chamber l9 inthe body II.

It should be noted that the beam 99 together with its reduced extension Ill wouldfunction exactly the same even though these were turned or otherwise shaped from a single unit; however, such construction would be somewhat more expensive from a production standpoint than the pressed co-axial fitting relationship between the III serving as a floating beam on proximate to thelower extremity 94 thereof for registry between two furcations 49-49 in a lever 91 that is disposed in the chamber [9 and has an offset arm 99 extending through an opening 99 (Figure 13) in the wall I9 of the body II.

The offset arm 49 is iournalled in a correspondingly sized bore 99 provided in the bottom plate 9| constituting a part of the indicator mechanism as will appear more fully hereinafter. The bottom plate 9| constitutes a part of the indicator casing and is fixed to the wall 19 of the wrench body II by means of threaded studs 92-99. The lever arm 99 has an enlarged peripheral shoulder 94 terminating in a reduced stud 99 over which is pressed an apertured arm 99 of a gear segment 91. The gear segment 91 meshes with a pinion 99 mounted on a stub shaft 99 which is iournalled in axial aligned bores 99 and 9| provided in-the casing plate 9| and a bracket plate 92 in parallel spaced relation therewith;

The bracket plate 92 is, in this instance, sub stantially T-shaped and is held or mounted in spaced parallel relation to the indicator casin bottom 9| by means of threaded studs 99, in this instance three, projecting through'the extremities thereof for engagement with correspondingly-threaded bores 99 (Figure 12) formed in the bottom indicator casing plate 9|. It should be observed that the fastening studs 99 are provided with an enlarged shank 99 serving as a spacer collar beyond the reduced threadedextremity thereof that engages the correspondingly threaded bores 99 (Figure 13), thereby maintaining the T-shaped bracket 92 in spaced relation with the indicator casing bottom plate 9|. The bracket 92 also serves as a bearing for the reduced extremity 99 of the lever arm 99 to insure the proper mounting of the gear segment 51 and maintaining the meshing engagement thereof with the pinion 99.

' A- spiral spring 99 envelope the stub shaft 99 on which the pinion 99 is mounted or integrally formed, to normally urge or return the indicator instrumentalities to an initial position. A calibrated dial 91 is mounted in a cylindrical collar 99 that threadedly engages the bottom plate 9| as at 99 to constitute a casing for the indicator instrumentalities. A pointer 19 is fixed to the reduced extremity of the pinion shaft 99 which projects beyond the indicator dial 9'! to designate in foot pounds ,the'torque exerted in tuming a nut or other fastening expedients by proper engaging attachment with the polygonal shank 29 while the turning force is applied to the handle II. A glass or other transparent crystal II is fitted to the indicator casing .99 to preclude obstruction to the pointer 19 and avoid the en-.

trance of foreign substances therein which would impair the accuracy and operation of the indicating instrumentalities.

This flexes'the beam 34-40'in one direction or the other depending upon the direction of the applied force to the handle l0, and this flexing will vary proportionately to the force applied to flex the beams 34-40 as indicated by the dotted outline thereof in Figure 8. The beam 34 together with its reduced extension 40 is preferably.tumed or otherwise shaped from a high quality steel alloy that has limited flexibility and a comparatively high elastic limit so that it will uniformly flex and return to its initial position to provide accurate readings within the range and elastic limit thereof without variation within ordinary requirements. Any number of high quality steel alloys may be used for this purpose, and by way of example the beam 34-40 can be advantageously constructed from an oil hardened tool steel.

It will be observed from the foregoing description of an illustrative embodiment constituting the subject matter hereof, that clockwise rotation imparted to the handle l (viewed from Figure 1) during the engagement of the polygonal shank 38 with a nut or other fastening implement, will cause flexing of the beam ends 34-40 as shown in the dotted outline in Figure 8. This action will cause slight longitudinal displacement of the beam 34-40 relative to its mount 32 and the latter will simultaneously rotate for a fractional extent to'facilitate the displacement of the beam 34-40 in opposite di.-.

rections responsive to the flexing thereof. The flexing of the beam 34-40 will correspondingly displace the pointer 10 which is connected to indicator instrumentalities calibrated to the selected size or capacity of the beam 34-40.

Then, too, it should be appreciated that the attachment of the indicator casing 60 with its bottom plate 5| on the body wall l5 aways maintains the indicator instrumentalities in operative connection with the beams 34-40, thereby rendering the cover, plate II removable for inspection, replacement, and cleansing purposes without interfering with the setting and operative connection between the beam extensions and the indicator lever 41. The operative connection of the indicator lever 41 to the terminal free end of the beams 34-40 also provides for the measurement of the torque at the point of maximum deflection of the torque resisting beam 34-40, thereby affording more accurate measurements than would otherwise be possible.

With the arrangement of parts above described, a very simple, dependable and accurate torque resisting and measuring beam 34-40 has been incorporated into a wrench or otherturning devices without sacrificing compactness or en-' cumbering the turning tool with any objectionable added weight. Various changes may be made in the embodiment of the invention herein specifically described without departing from or sacrificing any of the advantages of the invention or any features thereof, and nothing herein shall be construed as limitations upon the invention, its concept or structural embodiment as to the whole or any part thereof except as defined in the appended claims.

I claim:

ing carried by said handle member and engaging said beam intermediate the extremities thereof, and torque indicating means operatively connected to the free extremity of said yieldable beam.

2. In a torque wrench, the combination with a handle member, of a turning head member journailed in one end of said handle member, a yieldable torque resisting beam anchored in said tuming head member, a bearing slidably engaging said beam intermediate the extremities thereof and joumalled in said handle member, and callbrated indicating means operatively connected to the free extremity of said yieldable beam.

3 3. In a torque wrench, the combination with a handle member, of a turning head member joumalled in said handle member, an elongated yieldable torque resisting rod anchored at one extremity thereof to said head member, a bushing joumalled in said handle member and slidably engaging said yieldable rod intermediate the extremities thereof, said elongated yieldable rod terminating in a free extremity beyond said bushing, and torque indicating means operatively connected to the free extremity of said yieldable rod which is displaced responsive to applying force to said handle means.

4. In a torque wrench, the combination with a handle member, of a turning head member journailed in said handle member, an elongated cylindrical and yieldable torque resisting rod anchored at one extremity thereof to said head member, a bushing joumalled in said handle member and engaging said yieldable rod intermediate the extremities thereof, said elongated yieldable rod terminating in a free extremity beyond said bushin a smaller rod projecting from the free extremity of said elongated yieldable rod, and torque indicating means operatively connected to the free extremity of said last named rod which is displaced responsive to applying force to said handle means.

5. In a torque wrench, the combination with a handle member, of a turning head member joumalled in said handle member, an elongated cylindrical and yieldable torque resisting rod .of substantially uniform diameter anchored at one extremity thereof to said head member, a bushing joumalled in said handle member and slidably engaging said yieldable rod intermediate theextremities thereof, said elongated yieldable rod terminating in a free extremity beyond said bushing and extending along a longitudinal median line of said handle member, and torque indicating means operatively connected to the free extremity of said rod whichis displaced responsive to applying force to saidhandle means.

6. In a torque wrench, the combination with a chambered handle member, of a turning head member joumalled in said handle member, an elongated cylindrical and yieldable torque resisting rod. of substantially uniform diameter anchored at one extremity thereof to said head member, a bushing journalledin said handle member and slidably engaging said yieldable rod intermediate the extremities thereof, said elongated rod terminating in a free extremity beyond 1. In a torque wrench, the combination with g a handle member, of a turning head member joumalled in one extremity of said handle memher, a yieldable torque resisting beam anchored in said turning head member, a supporting bearsaid bushing and extending along a longitudinal median line of saidhandle member, torque indicating means operatively connected to the free extremity of said rod and which extremityis displaced in response to the application of force to said handle means, and a cover plate attached to said chambered handle member to cooperate therewith in confining said torque resisting rod.

- nailed in said handle member, an elongated cylindrical and yieldable torque resisting rod of substantially uniform diameter anchored at one extremity thereof to said head member, a bushing journalled in said handle member and slidably engaging said yieldable rod intermediate the extremities thereof, said elongated rod terminating in a free extremity beyond said bushing, a smaller rod projecting from the i'reeextremity of said elongated rod and extending along a longitudinal median line of said handle member, and torque indicating means operatively connected to the free extremity of said last named rod and which extremity is displaced in response to the application of force to said handle means.

8. In a torque wrench, the combination with a chambered handle member, of a turning head member journalled in said handle member, an elongated cylindrical and yieldable torque resisting rod of substantially uniform diameter anchored at one extremity thereof to said head member, a bushing joumalled in said handle member and slidably engagin said yieldable rod intermediate the extremitiesthereof, said elongated rod terminating in a free extremity beyond said bushing, a smaller rod projecting from the free extremity of said elongated rod and extending along a longitudinal median line of said handle member, torque indicating means operatively connected to the free extremity of said last named rod and which extremity is displaced in 7 response to the application of force to said handle means, and'a cover plate attached to said chambered handle member to cooperate therewith in confining said torque resisting rod.

9.111 a torque wrench, the combination with a handle member, of a turning head member journalled in said' handle member, an elongated cylindrical and yieldable torque resisting rod anchored at one extremity thereof to said head member, a bushing jou'rnalled in said handle member and slidably eng i said yieldable rod intermediate the extremities thereof, said elongated rod terminating in a free extremity beyond said bushing, a smaller rod projecting from the free extremityoi said elongated rod, a pin projecting transversely from said smaller rod extremity, torque indicating means operatively mounted on said handle member, a furcated lever extending from said indicating means and cooperating wlthsaid pin connected to the free extremity of said last named rod and which extremity is displaced in response to the application of force to said handle means. a r

10. In a torque wrench, the combination with a handle member, of a turning head member journalled in said handle member, an elongated yieldable torque resisting rod of substantially uniform cross-section anchored at one extremity thereof to said head member, a guide in said handle member for reciprocally receiving said yieldable rod intermediate the extremities thereof, said elongated rod terminating. in a free extremity beyond'said guide, a smaller rod projecting from the free extremity of said elongated rod and extending along a longitudinal median line 01' said handle member, a pin projecting transversely from said smaller rod extremity, torque indicating means operatively mounted on said handle member, a iurcated lever extending from said indicating means and freely cooperating with said pin connected to the free extremity of said last displaced inresponse to the application oi force tosaidhandlemeanswithsaidturninghead member in registry with a part to be turned.

11. In a torque wrench, the combination with a chambered handle member, of i a turning head -'member journalled in said handle member, an

elongated cylindrical and yieldable torque resistingrod oi. substantially uniform diameter anchoredat one extremitythereof to said head member, a bushing in said chambered handle member to reciprocally receive said yieldable rod intermediate the extremities thereof, said bushing beingjournalled in said handle member, said elongated rod terminating in a free extremity beyond said bushing a smaller rodprojecting from the free extremity of said elongated rod and extending along a longitudinal median line of said handle member, a pin projecting transversely from said smaller rod extremity, torque indicating means operatively mounted on said handle member, a furcated lever extending from said indicating means and cooperating with said pin connected to the free extremity of said last named rod and which extremity is displaced in response to the application of force to said handle means.

12. In a torque wrench, the combination with a chambered handle member, of a turning head member journalled in said handle member, an elongated cylindrical and yieldable torque ruisting rod of substantially uniform diameter anchored. at one extremity thereof to said head member, a bushing journalled in said handle member and slidably engaging said yieldable rod intermediate the extremities thereof, said elongated rod terminating in a free extremity beyond said bushing, a smaller rod oisubstantially uniform diameter projecting from the free extremity of said elongated rod and extending along a longitudinal median line of said handle member, a pin projecting transversely from said smaller rod extremity, torque indicating means operatively mounted on said handle member, a furcated lever extending from said indicating means into said chambered handle memberand cooperating with said pin connected to the free extremity of said last named rod and which extremity ,is displaced in response to the applicationof .rorce to said handle means. i

13. A torque wrench comprising, an elongated body member having a grip portion at one end thereof, a head member rotatably carried by the other end oi. said body member, an elongated torque resisting beam disposed substantially parallel with respect to said body and yieldably opposing relative rotation of said members, indicating means, said head member, beam, indicating means, and grip portion being arranged in longitudinally disposed relation in the order named, and means projecting from the end of said beam nearest said grip portion and connecting said end of said beam with said indicating means. i

14. A torque wrench comprising, an elongated body member havinga grip portion at onerend thereof, a head member rotatably carried by the other end 01. said body member, a yieldable torque resisting beam having one end thereof connected to said head member and its opposite end flexibly connected with said body member, indicating means, said head member, beam, indicating means, and grip portion being arranged in iongitudinally disposed'relation in the order named, and means connecting said opposite end of said named rod and which extremity is beam with said indicating means.

15. A torque wrench comprising, an elongated body member having a'- grip portion at one end thereof, a head member rotatably carried by the other end of said body member, a yieldable torque resisting beam carried by said head member and flexibly connected to said body member, indicating means, said head member, beam, indicating means, and grip portion being arranged in longitudinally disposed relation in the order named with said indicating means disposed in close proximity to said grip portion where it may readily be observed by the wrench operator, and means including an extension on the end of the beam adjacent to said gripportion adapted to engage said indicating means and operate the latter as said beam is flexed.

16. A torque wrench comprising, a body member having a gr p Portion at one end thereof, a

and having one end rigidly connected to one of said members and its other end flexibly connected to the other of said members so as to yieldingly resist relative rotation of said members, an indicator carried by one of saidmembers in close proximity to said'grip portion and having an operating-part, and means for operating said indicator as said beam is flexed which includes an extension on said other end of said beam operably engaged with said operating part.

17. A torque wrench comprising a body member having a grip portion at one end thereof, a head dicator as said beam is flexed which includes a longitudinally projecting extension on the end of said beam nearest said grip portion operably engaged with said operating-part.

. 18. A torque wrench comprising, a body member, a head member rotatably carried by said body member, a torque resisting beam carried at one end by one of said members, means providing a pivotal connection between the other end of said beam and the other of said members, indicating means, and means for directly connecting the end portion of said'beam remote from said head member to said indicating means.

19. A torque wrench comprising, a body member, a head member rotatably carried by said body member and having provision for engagement with the work, ayieldable torque resisting beam having one end portion connected'to said head member and extending away therefrom longitudinally of said body member, means providing a pivotal connection between the opposite end portion of said beam and said body member, indicating means, and means directly connecting the pivotally-connected end portion of said'beam to said indicating means. I

20. A torque wrench for use with an indicator for measuring the force applied to the work comprising, a body member, a head member rotatably carried by said body member and having provision for engagement with the work, an elongated torque resisting beam carried by one of said members, a flexible connection betweensaid beam and the other of. said members, whereby said beam yieldingly resists relative rotation of said members, and indicator-operating means directly connected to the end portion of said beam remote from said head member to actuate said indicator to measure the flex of said beam.

' 21. A torque wrench comprising, a pair of rock ably connected members, one of which is adapted to' be operably engaged with the work and the other is adapted to receive the pressure to be applied to the work, a torque resisting beam hav- 1 ing one end thereof carried by one of said members and having its opposite end connected to the other of said members for yieldably resisting relative rock movement of said members, said connection being such as to provide for free flexing movement of said opposite end of said beam,

indicating I means, and means for directly connecting said indicating means to said beam at its 7 end having free flexing movement;

22. A torque wrench comprising, an elongated body member, a head member rotatably connected to said body member, a substantially cylindrical torque resisting beam between said body and head members and connected thereto at its opposite end portionsfor yieldably resisting relative rotation of said members, indicating means, and an axial extension projecting from one end portion of said cylindrical beam and having operative engagement with said indicating means, whereby to measure the flex of said cylindrical beam responsive to the application of force to said body member.

23. A torque wrench comprising, a body 'mem- I ber, a head member rotatably carried by said body member and having provision for engagement with the work, a yieldable torque resisting beam carried by said head member and extending away therefrom longitudinally of said body member, means connecting the end portion of said beam opposite said head member to said body member, -said means permitting pivotal movement as well as longitudinal slide movement .of the end portion of the beam relative to said body member, indicating means, and an extension on the body-connected end portion of said beam operably connected to said indicating means for measuring the flex of said beam as igigdhead and body members are relatively ro- 24 A torque wrench comprising, a body member, a head member rotatably carried by said body member and having provision for engagement with the work, a yieldable torque resisting beam connected at one end portion to said head member and extending away therefrom longitudinally of said body member, means providing a pivotal connection between the opposite end portion of said beam and said body member, in-

. otally-connected end portion of said beam operably connected to said indicating means for indicating the flex of said beam.

25. A torque wrench comprising, a chambered casing, a detachable cover plate forsaid casing,

a head member rotatably supported in said casing adjacent one end thereof, a torque resisting beam housed in said casing and having one end,

connected to said head member and its other end flexibly connected to said casing at a point longitudinally removed from said head member;

an indicator carried by said casin and means supported by the casing-connected end portion of said beam and operatively connected with saidindicator for operating the latter, said head member, beam, indicator, and means being so supported independently ofv said cover that said cover may be removed without disturbing said inotally dicator and the operative wrench parts. I

28. A torque wrench comprising an elongated chambered body member having a grip portion at one end thereof, a head member rotatably carried inthe chamber of said body member, said relationship of the head member having an extension adapted to receive 'a work-engaging member. a yieldable torque rasistingbeam in said chamber opposing relative rotation of said members, indicating means car- .ried by the top wall of said chamber and operable upon relative rotation of said rotatable members, said head member, beam, indicating means, and r p portion being arranged in ionitudinally dispo e and a detachable cover plate for said chambered body member arranged so that it maybe removed without disturbing the operative relationship of the wrench parts, said cover plate having an opening'through which said extension projects and being arran ed so as to confine said head member against substantial axial movement berelation in the order named,

* head member having an enlarged portion in said.

tween said top wall'and the innersurfaceot said cover plate. g

27. A torque measuring wrench comprising, a handle member, a work-engaging member pivbore formed therein and extending across the axis of rotation of said work-engaging member, a normally straight spring bar yieldably opposing supported adjacent one end of said handle member, said work-engaging member having a torque resisting beam responsive to applying force to said handle member.

- 30. In a torque wrench, the combination with I a handle member, of a turning head member journaled in said handle member, an elongated and yieldable torque resisting rod interposed between said handle member and said turning head member. and connected to said turning head member, a rod bearing iournaled in said handle member to freely receive said rod therethrough, and calibrated indicating means operatively connected to the free. extremity of saidyieldable rod.

31. A torque wrench comprising: a handle member including an elongated body member having a chamberextending throughout substantially the full length thereof, said body having a longitudinally extendinggrip portion at one end thereof; an indicator carried by said handle member, said indicator being located at the end of said chamber nearest to said grip portion; a

chamber and .a relatively smaller, portion extending exteriorlyof said chamber and adapted to be operatively connected with the work;

elongated substantially cylindrical rod means in said chamber, one end of said elongated rod means being fixedly secured to the enlarged portion of said head member and extending radially relative rock movement of said work-engaging member and said handle member, said spring bar having one end thereof fixedly mounted in said bore and having its opposite end arranged to have a force applied thereto through said handle member, indicator means responsive to flexing of said spring bar and consequent relative rock movement of said work engaging and handle members for indicating the force applied to the work, and means operatively connecting said opposite end of said spring bar with said indicator bar and consequent relative rock movement of said work-engaging and handle members for indicating the force applied to the work, and means including an'element connecting said pivotallyconnected end of said spring barwith said indicator means.

29. In a torque wrench, the combination with an elongated wrench body member, of a handle member extending from one 'end of said body member and of'substantially lesser length than said body member, a turning head member oper-.

atively connected to said body member proximate to the other end thereof, a-yieldable elongated torque resisting beam extending between said handle member and said turning head member and connected to said turning head member, and calibrated indicating means operatively connected to the free extremity of said torqueresisting beam to measure the fiex of said yieldable from said enlarged portion and lengthwise of said chamber toward-said grip portion, said en-.

larged portion of said head member. being so arrangedand operatively connected with said handle member that it can turn relative to said handle member in proportion to the force applied to the work, the opposite end of said elongated rod means being free and unrestrained against movement in opposite directions in said chamber, said free end being moved upon turning of said enlarged portion of said head member relative to said handle member; and means between said indicator and'the free end of said elongated. rod means and extending angularly of the free end of said elongated rod means operatively connecting the free end of said elongated rod means to said indicator to actuate said indicator upon movement of the free end of said elongated rod means.

32. A torque wrench comprising: a handle member including a body having a chamber extending throughout substantially the full length thereof, and a grip portion extending longitudinally from said body; indicator .means carried. by said handle member adjacent one end of said chamber; a preassembled unit including a head member and an elongated substantially cylindrical rod means, said preassembled unit being adapted. tobe inserted bodily into said chamber, said head member having an enlarged portion received in said chamber and a relatively smaller portion extending exteriorly of said handle adjacent the opposite end of said chamber-and adapted to be operatively connected with the work, said elongated rod means having one end thereof. fixedly secured to the enlarged portion of said head member and ex-' tending lengthwiseof said chamber toward said grip portion, said enlarged portion of said head member being so arranged and operatively connected with said handle member that it can turn relative to said handle member in proportion to the force applied to the work, the opposite end ofsaid elongated rod means terminating at a point beneath said indicator means and being free and unrestrained against movement in opactuate said indicator means in response to the application of force to said handle member, said means including an operating part on said indicatormeans and a coupling part on the free end 5 of said elongated rod means.

I KENNETH R. LARSON. 

